Touch sensitive devices have become popular as input devices to computing systems due to their ease and versatility of operation as well as their declining price. A touch sensitive device can include a touch sensor panel, which can be a clear panel with a touch sensitive surface, and a display device, such as a liquid crystal display (LCD), that can be positioned partially or fully behind the panel or integrated with the panel so that the touch sensitive surface can cover at least a portion of the viewable area of the display device. The touch sensitive device can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location often dictated by a user interface (UI) being displayed by the display device. In general, the touch sensitive device can recognize a touch event and the position of the touch event on the touch sensor panel, and the computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event. Additionally, touch sensitive devices can also accept input from one or more active styli.
As touch sensing technology continues to improve, variable display rate displays can be used to save power when displaying static images or slowly changing images, or to improve performance in computationally intensive graphical environments (e.g., gaming environments). However, variable display rate operation can disrupt the synchronization between the display functions and various touch and/or stylus sensing functions, thereby degrading the performance of the device.